Injection molding processes involve the injection of softened or liquidized material into a mold having a cavity designed as invert geometry to the geometry of the desired final product. The injected material is solidified in the mold either via a physical process, e.g. thermal phase transition or via a chemical process, e.g. cross-linking or condensation polymerization. Injection molding processes are accompanied by elevated temperatures and high stresses, which are required for rapid and efficient forming of the intended part. Moreover, the injection molding processes are usually implemented in mass production so the molds have to withstand thousands and even millions of cycles during their lifespan.
Molds for injection molding may be manufactured from various materials. The majority of molds are made of metals, such as steels or aluminum alloys. These metallic molds are generated by a combination of different methods, most of which are subtractive methods, such as Computer Numerical Control (CNC) milling Subtractive methods are expensive, thus limiting the use of these molds to very large production series.
Less expensive production methods for manufacturing molds for injection molding involve the use of three-dimensional (3D) printing or 3D fabrication processes of thermosetting polymers. However, such molds may exhibit inferior properties relative to metallic molds (e.g., shorter life cycle of the mold) and inferior properties of the final product (e.g., dimensional distortions or geometrical inaccuracies).
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.